partial class Examples
{
  private static List<RhinoObject> m_line_objects = new List<RhinoObject>();

  public static Result DisplayOrder(RhinoDoc doc)
  {
    // make lines thick so draw order can be easily seen
    var dm = DisplayModeDescription.GetDisplayModes().Single(x => x.EnglishName == "Wireframe");
    var original_thikcness = dm.DisplayAttributes.CurveThickness;
    dm.DisplayAttributes.CurveThickness = 10;
    DisplayModeDescription.UpdateDisplayMode(dm);

    AddLine(Point3d.Origin, new Point3d(10,10,0), Color.Red, doc);
    AddLine(new Point3d(10,0,0), new Point3d(0,10,0), Color.Blue, doc);
    AddLine(new Point3d(8,0,0), new Point3d(8,10,0), Color.Green, doc);
    AddLine(new Point3d(0,3,0), new Point3d(10,3,0), Color.Yellow, doc);
    doc.Views.Redraw();
    Pause("draw order: 1st line drawn in front, last line drawn in the back.  Any key to continue ...");

    //all objects have a DisplayOrder of 0 by default so changing it to 1 moves it to the front.  Here we move the 2nd line (blue) to the front
    m_line_objects[1].Attributes.DisplayOrder = 1;
    m_line_objects[1].CommitChanges();
    doc.Views.Redraw();
    Pause("Second (blue) line now in front.  Any key to continue ...");

    for (int i = 0; i < m_line_objects.Count; i++)
    {
      m_line_objects[i].Attributes.DisplayOrder = i;
      m_line_objects[i].CommitChanges();
    }
    doc.Views.Redraw();
    Pause("Reverse order of original lines, i.e., Yellow 1st and Red last.  Any key to continue ...");

    // restore original line thickness
    dm.DisplayAttributes.CurveThickness = original_thikcness;
    DisplayModeDescription.UpdateDisplayMode(dm);

    doc.Views.Redraw();
    return Result.Success;
  }

  private static void Pause(string msg)
  {
    ObjRef obj_ref;
    var rc = RhinoGet.GetOneObject(msg, true, ObjectType.AnyObject, out obj_ref);
  }

  private static void AddLine(Point3d from, Point3d to, Color color, RhinoDoc doc)
  {
    var guid = doc.Objects.AddLine(from, to);
    var obj = doc.Objects.Find(guid);
    m_line_objects.Add(obj);
    obj.Attributes.ObjectColor = color;
    obj.Attributes.ColorSource = ObjectColorSource.ColorFromObject;
    obj.CommitChanges();
  }
}
